The invention involves a motor cooling system in general, and in particular, a cooling system for a small appliance motor such as is used in a vacuum cleaner.
When in operation motors generate heat that must be dissipated in order to prevent the motor from overheating. This is particularly true when smaller motors are used to generate large amounts of power because as the more power that is generated, the hotter the motor becomes.
Various ways of cooling an operating motor are known in the art. These include the use of a fan, a heat exchanger, a cooling fluid and the passing of cooler air through the motor compartment.
Motors used in the operation of small appliances have, for the most part, been cooled by drawing ambient air from outside of the appliance, through the appliance housing and around the motor. This cooler ambient air acts as a heat exchanger as it mixes with the hot air generated by the motor thereby cooling the air immediately around the motor while exhausting the warmer air out of the housing.
Although somewhat effective, such a cooling process has a major drawback in that the cooling air is directed around the outside of the motor as opposed to passing directly through the inside of the motor where the heat is the greatest. Furthermore, in the design of most conventional appliances, warm air is exhausted out through the top of the appliance or motor housing.
By directing the flow of cooling air around the motor as opposed to directly through its interior, inefficient cooling results as the warmest part of the motor fails to contact the cooling air. This results in the motor operating at a warmer temperature. Because of this inefficiency, a cooling system that directed cooling air directly into the center of the motor would be an important improvement in the art.
Additionally, the exhausting of cooling air through the top of the appliance housing creates the possibility that water or some other type of liquid that is splashed or spilled on the housing could enter the housing thus resulting in the motor experiencing a short or being damaged in some other manner.
Because the injection of water or some other impurity into the motor housing of an appliance such as a vacuum cleaner could result in costly repairs or even the scraping of the appliance altogether, a cooling system having a cooling-air intake and cooling-air exhaust that would prevent liquids or other impurities from entering the motor compartment would be an important improvement in the art.
The invention involves a cooling system for providing cooling air for a motor having a shaft extending through an opening within the motor, the motor being contained within a vacuum cleaner housing having a top and a bottom. The inventive cooling system is comprised of a cooling-air inlet located in a side of a vacuum cleaner housing, a motor housing integral with the vacuum cleaner housing, the motor housing having a top portion defining a hole passing therethrough, with the hole having a first dimension and being in flow communication with the cooling-air inlet, a side wall surrounding the hole and extending from the top portion of the motor housing, thereby enabling the cooling air to flow from the motor housing through an interior of the side wall, a baffle circumscribing the motor, the baffle having a second dimension that is greater than the first dimension enabling the cooling air to pass through the opening in the motor along a length of the motor adjacent the shaft with at least a part of the motor positioned within the side wall, and a cooling-air exhaust outlet also located in the side of the vacuum cleaner housing in flow communication with the motor housing and spaced apart from and in flow communication with the cooling-air inlet.